Testosterone suppresses fertility and can leave people completely infertile over time. The hormone does this by stopping eggs being released from the ovaries.

Those who would like to one day have biological children should consider freezing their eggs before starting testosterone treatment or having surgery.

Genital reconstruction surgery – such as the removal of the ovaries, womb or fallopian tubes – may prevent them having biological children unless they use a surrogate.

In 1,229 transgender men, there were four cases of invasive breast cancer – a lower rate than among the general female population.

The authors concluded: ‘The absolute overall risk of breast cancer in transgender people remains low and therefore it seems sufficient for transgender people using hormone treatment to follow screening guidelines as for cisgender people.’

Research suggests a link between HRT and breast cancer.

The most recent figures show women aged 50 to 59 have a 23 in 1,000 chance of getting breast cancer, but for those taking combined HRT, there’s a 28 in 1,000 chance.

Adults who suffer gender dysphoria – a mismatch between their biological sex and gender identity – are offered hormone therapy.

Transgender women who were born male take oestrogen, which reduces their body hair and causes breasts to grow.

Transgender men take testosterone which causes them to build muscle and have more body and facial hair. (DailyMail)